The transmission on the PowerTorque Kenworth test drive was the Eaton Endurant XD, and it’s genuinely a transformed AMT in the K220. This is an all-new box, which has been developed as an AMT from the ground up.
Out on the road, this box is definitely a revelation, it is a game changer for North American designed transmissions. It combines the robust nature of the classic Eaton transmission with the high-level electronic sophistication we normally associate with AMTs developed in Europe.
In this brave new world, where Roadranger skills are no longer a given in the trucking industry, this is the kind of AMT Kenworth need to enable their customers to help them cope with the skill levels at the younger end of the workforce.
Of course, there is still a manual option available in the Kenworth range, but PowerTorque expects the experience of fleets, when they get their hands on the Endurant XD, to change a few minds and we can expect to see the proportion of trucks coming down the Bayswater production line to be fitted with AMTs to increase.
It has been a long climb back for Eaton after the less-than-ideal performance of the Autoshift and the limitations of the design of Ultrashift, in computerising the Roadranger. However, the team at Eaton have achieved an excellent quick changing, flexible and intuitive transmission, which a driver can leave in auto most of the time and get the job done as well as they can with the traditional box, if not better.
It’s a three by three by two box, with all of those gears able to combine to give the driver 18 gears, this design combination means there are three reverse gears available to the driver, and for certain applications that number can be increased to six reverse gears. This option would be useful on tasks like spreading gravel, in road work situations.
The Endurant is also available with a 0.7 overdrive reducing the rpm required at 100 km/h. The rear diffs on the truck tested were 1:4.11 which is quite standard diff on this Kenworth, meaning the engine is sitting at 1650 rpm at 100km/h.
Taller diffs are available which would bet the revs at cruising speed down to 1550rpm or even 1450rpm at 100km/h if the freight task allows and the desire for better fuel economy is there.
With the Endurant XD, the driver can choose to use it completely manually and just paddle the steering column stalk up and down. In some situations, this may be useful when the terrain is particularly difficult or the load problematic. This transmission is smarter than that and will make the right changes at the right 99-plus per cent of the time.
Leaving it in auto mode but keeping an eye on the truck and then intervening using the paddle when needed is a far better option and one which makes for more relaxed driving and reduces distraction. There is always the easy option, to leave it in auto and see how it copes.
In most driving tasks that is going to be sufficient. The skill of the driver will be knowing when to intervene and when to leave it alone. Add into this scenario the use of the active cruise control and the driver then becomes a virtual steering wheel attendant who has to keep an eye on things.
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